Assessing lactate stability at the minimum lactate steady state velocity in male trained middle-distance runners

Figures

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  Fig 1. Interindividual variability in oxygen consumption, carbon dioxide production, and substrate oxidation during 3000-m time trial. Note. This multi-panel figure illustrates individual responses (n = 15) in four key physiological parameters measured during a 3000-meter time trial: Top left (V̇O₂_3000): Oxygen uptake (mean ± SD = 3.83 ± 0.25 L·min ⁻ ¹); Top right (V̇CO₂_3000): Carbon dioxide output (3.47 ± 0.23 L·min ⁻ ¹); Bottom left (CHO_3000): Carbohydrate oxidation rate (239.75 ± 21.3 g·h ⁻ ¹); Bottom right (FAT_3000): Fat oxidation rate (10.13 ± 1.8 g·h ⁻ ¹). Dashed horizontal lines represent the group mean.

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  Fig 2. Lactate-pace relationship during the 6 × 800-m minimum lactate protocol.

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  Fig 3. Individual variability in lactate kinetics, MLaSS running velocity, glycolytic capacity, and metabolic responses. Note. Individual athlete values for key physiological variables measured during the Minimum Lactate Steady State (MLaSS) protocol. Panels include: Peak blood lactate, Post-recovery lactate, Lactate nadir, Running velocity at MLaSS (vMLaSS), Maximal lactate production rate (VLamax), oxygen uptake (V̇O₂), carbon dioxide output (V̇CO₂), Carbohydrate oxidation (CHO), and Fat oxidation (FAT). Each point represents one of the 15 athletes, with dashed lines indicating group mean ± SD.

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  Fig 4. Linear trends in blood lactate concentrations across 0, 10, 20, and 30 minutes during the minimum lactate steady state (MLaSS) stage. Note. Blood lactate concentrations were measured at 0, 10, 20, and 30 minutes during the Minimum Lactate Steady State (MLaSS) running stage for 15 trained athletes. Each color-coded line represents a different sampling time (0 min: black, 10 min: red, 20 min: blue, 30 min: green). Individual athlete values are shown alongside their respective linear regression fit curves, with slope, intercept, R2, adjusted R2, Pearson’s r, and residual sum of squares presented in the inset table.

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  Fig 5. Lactate responses across 0, 10, 20, and 30 minutes during the minimum lactate steady state (MLaSS) stage. Note. Individual lactate responses were measured at four time points (0, 10, 20, and 30 minutes) during the Minimum Lactate Steady State (MLaSS) running stage. Bars represent mean ± SD, while connecting lines show individual athlete trajectories (n = 15). Lactate increased sharply from baseline to 10 minutes (p < 0.001), followed by a reduction toward 20 minutes and a slight rise again at 30 minutes.

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  Fig 6. Individual V̇O2, V̇CO2, carbohydrate, and fat oxidation responses during the final 30 minutes of the minimum lactate steady state (MLaSS). Note. Individual athlete data for oxygen uptake (V̇O₂), carbon dioxide output (V̇CO₂), carbohydrate oxidation (CHO), and fat oxidation (FAT) measured during the 30 minutes of the Minimum Lactate Steady State (MLaSS) running stage. Each point represents one of 15 trained athletes, with dashed horizontal lines indicating group mean ± SD.